Effect of Administration of an Opioid Antagonist (Naloxane) to Treat Ovarian Cysts in Dairy Cows

The role of stress in the pathogenesis of ovarian cysts is believed to be mediated by the discharge of endogenous cortisol, which inhibits LH release. Endogenous opioid peptides are involved in many responses to stress. Therefore, the aim of this study was to determine the effect of epidural administration of Naloxone (NX) on cystic regression and follicle development leading to normal oestrus in dairy cattle.This study was conducted on 91 dairy cattle affected by follicular cysts, divided randomly into 3 groups.Group1 (n=30) cows were treated epidurally (lumbo-sacral) with 0.8 mg Naloxan hydrochloride (NX). Group2 (n=30) cows were treated epidurally with GnRH analogue (100 mcg gondorelin acetate). Group3 (n=31) cows were considered as control and received 5 ml normal saline epidurally.Although the results of this study showed that Naloxane was better than the other two groups to treat follicular cysts, there was no significant difference in differnnt criteria, such as CL formation, increasing plasma P4 concentrations and 1st service conception rates among 3 groups.